xfs: Replace macro XFS_DQUOT_TREE with a function

In preparation for combined pquota/gquota support, for the sake
of readability, change the macro to an inline function.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c
index 28a5e8a..8e707d3 100644
--- a/fs/xfs/xfs_qm.c
+++ b/fs/xfs/xfs_qm.c
@@ -70,7 +70,7 @@
 	void			*data)
 {
 	struct xfs_quotainfo	*qi = mp->m_quotainfo;
-	struct radix_tree_root	*tree = XFS_DQUOT_TREE(qi, type);
+	struct radix_tree_root	*tree = xfs_dquot_tree(qi, type);
 	uint32_t		next_index;
 	int			last_error = 0;
 	int			skipped;
@@ -189,7 +189,7 @@
 	xfs_dqfunlock(dqp);
 	xfs_dqunlock(dqp);
 
-	radix_tree_delete(XFS_DQUOT_TREE(qi, dqp->q_core.d_flags),
+	radix_tree_delete(xfs_dquot_tree(qi, dqp->q_core.d_flags),
 			  be32_to_cpu(dqp->q_core.d_id));
 	qi->qi_dquots--;
 
@@ -1471,7 +1471,7 @@
 	struct xfs_quotainfo	*qi = mp->m_quotainfo;
 
 	mutex_lock(&qi->qi_tree_lock);
-	radix_tree_delete(XFS_DQUOT_TREE(qi, dqp->q_core.d_flags),
+	radix_tree_delete(xfs_dquot_tree(qi, dqp->q_core.d_flags),
 			  be32_to_cpu(dqp->q_core.d_id));
 
 	qi->qi_dquots--;